1. Field of the Invention
The present invention relates to a CAD system to be used in team-based design, and particularly to improvements in undo and redo functions that the CAD system provides.
2. Description of the Related Art
Heretofore, when designing a relatively large apparatus having a large number of parts, such as an automobile, the exterior of the automobile to be designed is divided into a plurality of components as design units, and thereafter the various components are designed concurrently, namely, a team-based CAD system is adopted. In the CAD system to be used for this team-based design, a plurality of designers concurrently perform the design of the various components at various data processing terminals to achieve more efficient overall design and shorter design times. Furthermore, when each component contains a plurality of parts, the design of each component is assigned to designers and a team is formed for each component. Since each designer performs design tasks on individual terminals in this manner, all design details must be ultimately organized. By preparing a common component database in advance for each team designing one component and by having the designers in the team access the component database, savings in disk space and prevention of potential problems with other designers are achieved.
Furthermore, in the CAD system, CAD commands, such as design, modify, delete, and move, are executed by the operation of a keyboard or mouse, and while these operations can be reflected in the component database, a function is included to collect history information for each operation. For example, if a designer A and a designer B belonging to the same team concurrently perform operations in the procedure shown in FIG. 30 on separate terminals, these operations are recorded in sequence as history information in a history database provided to correspond to the component database and not particularly related to the designers. An example of the contents of this recorded history information is shown in FIG. 31. Although FIG. 31 is shown as a table for convenience, each type of history information is generated as a history object. Each xe2x80x9celementxe2x80x9d given in the figure refers to a graphic form to be drawn by a single command, such as line, circle, or square, and as a rule, one command is executed per operation and one graphic form is drawn. A single component is normally designed from combining a plurality of elements.
There are instances when it is desirable to cancel the drawn element in one operation. In general CAD systems, an undo function for canceling the last operation and a redo function for recovering the element canceled by the undo function are provided so as to improve the designing efficiency.
Heretofore, however, the operated procedure has been recorded in the history database as history information of the combined operations by different designers so that if, for example, designer B wishes to cancel the operation of xe2x80x9ccreation of element 4xe2x80x9d in a state where the operations given in FIG. 30 have been performed, the conventional undo function must be executed twice in accordance with the history information recorded in the history database shown in FIG. 31. Namely, designer B cannot cancel the operation of xe2x80x9ccreation of element 4xe2x80x9d unless the operation of xe2x80x9cdeletion of element 2xe2x80x9d performed by designer A is canceled with the undo function. Therefore, the operation of xe2x80x9ccreation of element 4xe2x80x9d cannot be canceled using the undo function if designer A does not acknowledge the cancellation of the operation of xe2x80x9cdeletion of element 2xe2x80x9d.
Therefore, in the prior art, even if one wishes to cancel only one""s last operation among the operations executed by designers in the same team and sequentially recorded in a mixed state, valid operations must also be canceled through use of the undo function. Alternatively, in the case where an element is returned to its original state if the undo function is executed, a new design task is performed corresponding to the execution of the undo function and is not efficient.
The present invention is intended to solve the above-mentioned problems, the object of which is to provide a CAD system for team-based design for providing the undo function, which allows the cancellation of operations on a designer basis, and the redo function, which redoes the operation canceled by the undo function on a designer basis.
In order to achieve the above-mentioned object, the CAD system for team-based design concerning the present invention comprises means for providing the undo function to sequentially record the contents of operations performed by each designer in design tasks, which a plurality of designers are to perform in teams, as history information into common history information storing means, and to cancel the last operation based on the order of the history information recorded in the history information storing means, history information collecting means for recording to the history information storing means, each time the designer performs an operation, history information, which includes information on the time the operation was performed, elements included in the design for which the operation was performed, the type of operation, the designer who performed the operation, and information representing the validity or invalidity of the operation that was set to valid, and undo function control processing means for canceling the operation that is the object when the undo function is executed and for changing to invalid the information representing the validity or invalidity of the operation corresponding to history information of the corresponding operation that has been recorded in the history information storing means. The undo function control processing means cancels the last operation that the operator performed when the operator executes the undo function.
Furthermore, the undo function control processing means is characterized by canceling, in accordance with mode selection by the designer when the designer executes the undo function, either the last operation performed by the relevant designer or the last operation according to the time of operation.
Furthermore, the CAD system comprises redo function control processing means for redoing an operation that was canceled by execution of the last undo function when the redo function is executed and for changing to valid the information representing the validity or invalidity of the operation corresponding to the history information of the relevant information that is recorded in the history information storing means, and is characterized by redoing the operation that was canceled by the designer executing the last undo function as a result of searching the history information storing means when the relevant designer executes the redo function.
Furthermore according to the mode selection by a designer when the designer executes the redo function, the redo function control processing means is characterized by redoing either the operation that was canceled by execution of the undo function by the relevant designer or the operation that was canceled by execution of the last undo function according to the time the undo function was executed.
Furthermore, the history information collecting means is characterized by managing the history information regarding one operation by grouping according to time base reference, element, and designer.
According to the present invention, the last operation performed by a designer who executed the undo function among the operations performed by the designer in a team can be retrieved and canceled.
Similarly, the designer who executed the redo function can restore the operation that was canceled by execution of the last undo function.
According to the present invention, when a designer executes the undo function, only the last operation that the designer performed can be canceled without canceling an operation by another designer in the same team.
Furthermore, when a designer executes the redo function, only the operation that the designer canceled by execution of the last undo function can be redone without redoing an operation of another designer in the same team.
Furthermore, in addition to the execution of the undo function and redo function per designer, the same functions with reference to the conventional time base can also be selectively executed.